1. Field of the Invention
This specification relates to a wireless access system and, more specifically, to a method and apparatus for performing uplink ranging in idle mode for network reentry.
2. Related Art
M2M Communication, Machine Type Communication (MTC)
M2M communication is described in brief below.
Machine to machine (M2M) communication as it is means communication between electronic devices. That is, M2M communication means communication between things. In general, M2M communication means wired or wireless communication between electronic devices or communication between a device and a machine which are controlled by human beings, but M2M communication is used to specially denote wireless communication between an electronic device and an electronic device, that is, devices. Furthermore, M2M devices used in a cellular network have lower performance or capability than common terminals.
There are many terminals within a cell, and the terminals may be classified depending on the type, class, service type, etc of the terminal. In particular, when machine to machine (M2M) communication (or machine type communication (MTC)) is taken into consideration, the total number of terminals will increase suddenly. M2M devices may have the following features depending on supported service.
1. A large number of terminals within a cell
2. A small amount of data
3. Low transmission frequency (may have periodicity)
4. A limited number of data characteristics
5. Not sensitive to time delay
6. Low mobility or fixed
In the case of a network reentry process in idle mode in an IEEE 802.16m system, a terminal in idle mode checks a paging message transmitted by a base station in the paging listening interval of its own paging cycle. If it is checked that the paging message is transferred thereto, the terminal in idle mode shifts to normal mode by randomly performing network reentry into the base station.
If numerous M2M devices in idle mode receive paging from a base station and perform network reentry into the base station at the same time, however, there is a high probability that a collision may occur because there are numerous M2M devices in an M2M (or MTC) environment.